Help wiring a timer switch

Discussion in 'General Electronics Chat' started by Jeremy, Sep 17, 2006.

  1. Jeremy

    Jeremy Thread Starter New Member

    Joined:
    Sep 17, 2006
    Messages:
    2
    I appologize if this is too elementary for most of you but if anyone can offer some advice I'd most appreciate it. I have a fan that plugs into a standard 120V outlet (3 pronged plug) that I want to control with a timer. I found a very nice timer that's desinged to replace a wall switch (ie, for controlling lights). What I wanted to do is mount it in a dual outlet box next to a 3 pronged outlet and wire in a 3 pronged cord. That way I'd have a "timer box" that I could plug into any outlet in the house which would then control the fan I plug into it.

    What's confusing me is that the timer switch comes with 4 wires (black=hot, white=common, red=load, and green=ground). The cord I want to wire in to the switch obviously only has three wires (black = hot, white = common, green = ground) which matches the way I undestand that wall switches get wired. So how do I wire a three pronged plug and outlet to a 4 wired switch? I had assumed that the switch just used three wires and broke the connection of the hot wire to turn my load on and off but apparently this is not the case. I assume that the solution is to wire two of the four wires together but that is just a guess and I don't intend to do anything without some guidance from someone who knows what they are doing. I am very confused and don't want to do something stupid with this circuit!

    Thanks for any help.

    Jeremy
  2. Søren

    Søren Active Member

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    Sep 2, 2006
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    Location:
    Denmark
    Hi,

    The timers black (hot) goes to the phase (hot) of the mains.
    The timers red (load) goes to the black (hot) of the switch/fan (as that is the load).
    The white is connected to the other white plus to the white from the mains.
    The green is connected to the other green plus to the green from the mains.

    The timer need to be connected to hot and neutral (what you call common) to work and to ground to be "safe".
    To supply the fan, it further needs an output, which is hot when the timer is supposed to drive the load connected to it and hence the four wires.
  3. Jeremy

    Jeremy Thread Starter New Member

    Joined:
    Sep 17, 2006
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    Soeren,

    Thanks very much for taking the time to reply. Yes, you are obviously right. I actually figured it out a couple of hours ago and eveything is working fine. In retrospect I don't know what I was thinking. What was confusing me was the red wire - it took a while for me to realize that it is the "output" hot wire from the switch. It seemed odd that the red wire would go to the load's black wire but once I realized that it made perfect sense. Thanks again for your help!

    Jeremy
  4. Søren

    Søren Active Member

    Joined:
    Sep 2, 2006
    Messages:
    273
    Location:
    Denmark
    Hi,

    Well that happens to us all from time to time - having a problem up close sometimes mean you loose the oversight :)

    Happy "timing".
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